1. Technical Field
The present invention relates to a projector attachable on a ceiling or a wall surface such as a lateral wall of a building, the projector including: a light source; an optical modulator that modulates a light beam emitted from the light source to form an optical image; a projection optical device that projects the formed optical image; and an exterior casing that accommodates the light source, the optical modulator and the projection optical device.
2. Related Art
There have been known projectors which modulate a light beam emitted from a light source in accordance with image information to form an optical image, the projectors projecting the optical image on a screen and the like in an enlarged manner. Such a projector is often used in a normal posture in which the projector is placed on an installation surface of a desk and the like such that the upside of the projector is up. However, the projector may also be used in a suspended posture in which the projector is attached on a ceiling and the like such that the upside in the normal posture is down. Accordingly, there has been also known a projector that has a structure enabling the projector to be attached on a ceiling and the like (see, for example, JP-A-2005-215144 (Page 15, FIG. 13)).
The projector disclosed in the document can be fixed on a ceiling by a fixing portion provided to a lower case of the projector such as an insert nut and a fixing member fixed on the ceiling such as a bolt.
However, in the projector disclosed in the document, when the fixing portion (such as the insert nut) covered with oil and the like is attached on the lower case, the oil may permeate the lower case, which may cause a chemical stress crack in the lower case. When the chemical stress crack occurs, the lower case may be damaged and the projector may fall off from the ceiling leaving the fixing portion on the ceiling. Hence, it is required to separately provide an anti-fall structure to the projector. As a result, the structure of the projector may be complicated and the manufacturing cost of the projector may be increased.
Due to such problems, there have been demanded projectors which have a simple structure but can prevent a fall of the projector even when the projectors are attached in the suspended posture.